Hydrogen gas fireplace

ABSTRACT

A burner for use in a hydrogen burning appliance that includes a gas enclosure defining a gas distribution chamber and a gas aperture, a burner having a combustion surface, a hydrogen gas source coupled to the gas enclosure, and a flame enhancement member positioned in a path of the combusting hydrogen. The hydrogen gas source supplies hydrogen gas to the gas chamber for distribution to the gas aperture for combustion of the hydrogen gas at the combustion surface. The flame enhancement member may alter properties of the flame such as the flame color.

FIELD OF THE INVENTION

The present invention generally relates to fireplaces, and more specifically relates to fireplaces that use hydrogen as a source of fuel.

BACKGROUND OF THE INVENTION

The use of hydrogen as a source of fuel has gained increased popularity in recent years as technology related to the production of hydrogen has improved and the public perception of safety related to hydrogen has gradually changed. Hydrogen fuel has many benefits and advantages over other commonly used sources of fuel. For example, combusting petroleum products (e.g., natural gas and liquid propane) and fibrous products (e.g., wood) in a heating appliance generates harmful gases such as carbon monoxide (CO) that must be exhausted. Providing exhaust vent systems for a heating appliance adds significant cost, time and space requirements when installing the heating appliance. In contrast, the byproducts of generating and combusting hydrogen are oxygen (O₂) and water (H₂O). These byproducts are not only safe for the environment, but are also desirable products that can be used for alternative purposes in a beneficial way. Thus, an exhaust system is not required when combusting hydrogen.

An associated advantage of combusting hydrogen relates to proper venting of an open front fireplace structure. Open front fireplaces typically have a certain amount of the combustion gases that spill out of the fireplace front, especially under conditions of back draft in the fireplace exhaust vent or negative pressure in the living space. Thus, the use of open front fireplaces for combusting typical fuels (e.g., petroleum based and fibrous products) has become very limited in the recent past due in part to higher air quality standards and an increases awareness of safety issues related to combustion gases. As noted above, byproducts of combusting hydrogen do not have to be exhausted, thus removing limitations to the use of an open front fireplace.

Another advantage with using hydrogen as a source of fuel relates to the relative simplicity of generating hydrogen fuel itself. Water is commonly used as a basis for hydrogen fuel production. In one example, sodium hydroxide is mixed with aluminum and water; the chemical reaction of which produces hydrogen gas. Another example hydrogen production system is an electrolyzer that generates hydrogen by charging water particles to create a polarity and then splitting the water particles with a charged proton exchange membrane. Many other types of hydrogen production are known or are being developed for use.

The use of hydrogen as a fuel also has some disadvantages. One disadvantage relates to storage of hydrogen and delivery of hydrogen to an end user. Unlike natural gas and other petroleum based and fibrous materials that are used for energy, there is presently no infrastructure or system established for mass production and/or delivery of hydrogen fuel to an end user. As a result, the hydrogen fuel must be generated on site or delivered in relatively small quantities. Two example storage methods for hydrogen fuel are a pressurized tank in which the hydrogen fuel displaces water also contained in the tank, and a metal hydride foam which when charged with one polarity is able to retain hydrogen and when charged in the opposite polarity releases the hydrogen.

The use of hydrogen as a fuel to create a decorative flame or to produce heat in a heat generating appliance also has some disadvantages. One disadvantage relates to the appearance of combusting hydrogen as a decorative flame. Combusting hydrogen is relatively colorless and the flame is relatively hot compared to flames of other known combustible materials. Also, the flame appearance is linear and involves very little movement of the flame itself (flame movement being known generally as “flicker”). Decorative flames typically have a yellow or orange tint and flicker significantly at any flame size.

Structures and methods relating to combusting hydrogen in a heating appliance that address these and other disadvantages of combusting hydrogen would be an advance in the art.

SUMMARY OF THE INVENTION

The present invention generally relates to fireplaces, and more specifically relates to fireplaces that use hydrogen as a source of fuel. One aspect of the invention relates to a gas fireplace that includes a combustion chamber enclosure, a burner, and a flame enhancement member. The combustion chamber enclosure defines a combustion chamber. The burner is disposed in the combustion chamber and defines apertures positioned to provide hydrogen gas to a surface of the burner for combustion. The flame enhancement member is positioned relative to the surface of the burner to engage the combusting hydrogen thereby improving visibility of the combusting hydrogen.

Another aspect of the invention relates to a burner for use in a hydrogen burning appliance that includes a gas enclosure defining a gas distribution chamber and a gas aperture, a burner having a combustion surface, a hydrogen gas source coupled to the gas enclosure, and a flame enhancement member positioned in a path of the combusting hydrogen. The hydrogen gas source supplies hydrogen gas to the gas chamber for distribution to the gas aperture for combustion of the hydrogen gas at the combustion surface.

A further aspect of the invention relates to a method for generating a visible hydrogen flame. The hydrogen flame is provided in a gas enclosure that defines a gas distribution chamber and a combustion surface having a gas aperture formed therein. The method includes supplying hydrogen gas to the gas distribution chamber, passing the hydrogen gas out of the gas aperture, combusting the hydrogen gas at the combustion surface, and passing the combusting hydrogen gas through a flame enhancement member to alter a color of the combusting hydrogen gas.

Another aspect of the invention relates to a fire display assembly that includes a burner, a flame enhancement member, and a support platform. The burner defines apertures positioned to provide hydrogen gas to a surface of the burner for combustion. The flame enhancement member is positioned relative to the surface of the burner to engage the combusting hydrogen thereby improving visibility of the combusting hydrogen. The platform is configured to support the burner and flame enhancement member from vertically beneath the burner and flame enhancement member. The burner is open to ambient air on all sides such that the fire display assembly is configured as an open fire pit.

The above summary of the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. Figures in the detailed description that follow more particularly exemplified embodiments of the invention. While certain embodiments will be illustrated and described, the invention is not limited to use in such embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of the following detailed description of various embodiments in the invention and in connection with accompanying drawings, in which:

FIG. 1 is a front perspective view of an example fireplace that includes a burner assembly configured to combust hydrogen to produce flame;

FIG. 2 an exploded view of the fireplace shown in FIG. 1 illustrating the burner assembly as a separate unit and the burner assembly coupled to a hydrogen fuel source;

FIG. 3 is a perspective view of the tube burner shown in FIGS. 1 and 2;

FIG. 4 is a top view of the tube burner shown in FIG. 3;

FIG. 5 is a top perspective view of a pan-shaped burner according to principles of the present invention;

FIG. 6 is an exploded view of the pan-shaped burner shown in FIG. 5;

FIG. 7 is a side view of the pan-shaped burner shown in FIG. 5;

FIG. 8 is a top perspective view of an example burner assembly that is configured to combust hydrogen to produce a flame according to the principles of the present invention;

FIG. 9 is a side view of the burner assembly shown in FIG. 8;

FIG. 10 is a front view of the burner assembly shown in FIG. 8;

FIG. 11 is a front perspective view of an example of ceramic molded burner according to principles of the present invention.

FIG. 12 is a top perspective view of a tube burner assembly with a contoured flame enhancement member coupled thereto according to principles of the present invention;

FIG. 13 is a top view of another example pan-shaped burner having a flame enhancement member formed thereon according to principles of the present invention;

FIG. 14 is a side view of the burner shown in FIG. 13;

FIG. 15 is a side view of another example fireplace that includes a smoke simulation assembly according to principles of the present invention;

FIG. 16 is a front perspective view of an example open fire display assembly according to principles of the present invention;

FIG. 17 is a side view of another example fireplace that includes a blower according to principles of the present invention;

FIG. 18 is an example circuit diagram illustrating components of an example ignition system for a hydrogen burner; and

FIG. 19 is a process diagram illustrating an example operation method according to principles of the present invention.

While the invention is amenable to various modifications and alternate forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the invention is not limited to the particular embodiments described. On the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention generally relates to fireplaces, and more particularly relates to fireplaces that use hydrogen as a source of fuel. The present invention also relates to methods of generating a visible hydrogen flame, methods of generating, storing, and delivering hydrogen to a hydrogen burner in a fireplace, and other methods and structures related to the use of hydrogen as a fuel in heating appliances such as fireplaces.

While the example embodiments of the present invention provided below are described in connection with example fireplaces, the present invention may be applicable to other systems or apparatuses such as furnaces and stoves. Principles of the present invention may be embodied in retrofit configurations that can be applied to existing fireplaces. Further, common venting systems and fireplace configurations such as a direct vent, a universal vent, a B-vent, a horizontal/vertical-vent, a dual direct vent, and a multisided unit having two or three glass panels as combustion chamber side panels may be used to exhaust unwanted byproducts (heat, water (H₂O) or oxygen (O₂)) of combusting hydrogen fuel. Such common venting systems and fireplace configurations may include an adjustable baffle member (not shown) that controls the flow of combustion byproducts into a venting system as desired (e.g., exhausting heat and water byproducts during the warmer summer months and not exhausting heat and moisture byproducts during colder, dryer winter months). While the present invention is not so limited, an appreciation of various aspects of the invention will be gained through a discussion of the examples provided below. Principles of the present invention may be best recognized in applications in which the combusting hydrogen is viewable as a decorative flame.

As used herein, a “combustion chamber” may include any structure that at least partially encloses a space in which a flame, simulated flame, or flame-related effect is generated by, for example, combusting material or generating a flame-related effect such as sound or light. A “combustion chamber” may be defined by one or more panels that permit viewing through the panel. A “combustion air enclosure” is defined as any enclosure that defines a chamber for holding combustion air for use in the combustion chamber. A “combustion fuel enclosure” is defined as any enclosure that defines a chamber for holding combustible fuel. A “flame enhancement member” is any solid material such as, for example, metal, metal alloy, or other material that alters a property of the combusting hydrogen. In one example, the flame enhancement member is a metal member that alters the visible color of the combusting hydrogen by, for example, ionizing the combusting hydrogen.

One example fireplace assembly 10 that includes features related to combustion of hydrogen is described and illustrated with reference to FIGS. 1-3. Fireplace 10 includes an outer enclosure 12, a combustion chamber enclosure 14, a burner assembly 16, a grate 18, and a fuel source 19.

The outer enclosure 12 may include an exhaust aperture 20, an intake vent 22, and an exhaust vent 24, although some or all of these features may not be required because of the limited combustion air requirements and the clean combustion byproducts of combusting hydrogen. The combustion chamber enclosure 14 includes rear, bottom, side, and front panels 30, 32, 34, 36, which together define a combustion chamber 38, wherein combustion of hydrogen occurs for the generation of heat. The panels of the combustion chamber enclosure 14 may include materials such as, for example, sheet metal, molded fiber material, or a combination of these materials. In one embodiment, the combustion chamber enclosure is constructed of a moldable material like that described in U.S. patent application Ser. No. 09/781,148, incorporated herein by reference.

Typically, the combustion chamber enclosure 14 is positioned within the outer enclosure 12 such that a plenum is defined there between in which air drawn in through the intake vent 22 can be heated by heat emanating from the combustion chamber 38 through the panels 30, 32, 34, 36. The heated air may be exhausted out of the exhaust vent 24 back into a living space, or vented to a remote location. Preferably, the combustion chamber enclosure is open at a front surface thereof to provide a more realistic fireplace setting. Because the byproducts of hydrogen combustion pose no health risks, the venting issues common to known open front fireplaces are not relevant; with the possible exception of venting heat.

A front panel (not shown) made of a clear material that provides viewing of the combustion chamber 38 while sealing the combustion chamber 38 may be included in some embodiments. The addition of a front panel (either a fixed or removable panel) may improve safety and help control venting of the combustion byproducts. Still further embodiments may include modified panels of the combustion chamber enclosure 14 to alter the flow of air and combustion products into and out of the combustion chamber 38. For example, one embodiment may include a bottom panel 32 having a plurality of apertures formed therein and the fireplace includes a blower or a plurality of blowers positioned in fluid communications with the apertures so as to provide either a stream of fresh air into the combustion chamber or to provide a suction force that draws combustion products and heat out of the combustion chamber.

The burner assembly 16 includes a valve 40, a first fuel line 42, a base 44, an ignition/pilot system 46 having a thermopile 48 and a pilot burner 49, a tube burner 50, a flame enhancement member 52, and a second fuel line 54. The first fuel line 42 is coupled to the fuel source 19, and the second fuel line 54 couples the valve 40 to the tube burner 50. Typically, the fuel source 19 provides hydrogen gas for combustion. Alternatively, mixtures of hydrogen gas and other combustible gases, such as natural gas and propane, can be burned within the combustion chamber enclosure. The amounts of hydrogen and other gases can be metered, regulated, or prepared to modify the heat of combustion and visual appearance of the flame.

The fuel source 19 can be placed within the plenum created between the combustion chamber enclosure 14 and the outer enclosure 12. Alternatively, the fuel source 19 can be located in remote location and the hydrogen gas can be supplied for combustion by a supply line. One hydrogen generating fuel source is an electrolyzer. An exemplary electrolyzer can be obtained from HYDROGENICS located in Mississauga, Ontario, Canada.

As shown in FIG. 3, the tube burner 50 includes a plurality of apertures 56 sized and configured for passing hydrogen fuel from the second fuel line 54 to an outer surface of the tube burner 50 for combustion when ignited by the system 46. The burner 50 also includes a mounting bracket 58 for mounting the tube burner to the base 44 and the second fuel line 54. The valve may be any valve that is suited for controlling the flow of hydrogen, such as, for example, the valve shown and described in U.S. Pat. No. 6,520,199 and U.S. patent application Ser. No. 10/788,751, which patent and application are incorporated herein by reference in their entirety. The burner 50, although shown having a linear, cylindrical shape, may be shaped with contours and different cross-sectional shapes in other embodiments.

The ignition system 46 may be any system or device that ignites the hydrogen fuel to begin combustion of hydrogen at the burner 50. The thermopile 48 is designed to recognize the presence of combusting hydrogen fuel. When the thermopile 48 recognized the presence of combusting hydrogen via the pilot burner 49, then the ignition system signals the valve 40 to deliver hydrogen fuel to the burner 50 for combustion. When the thermopile does not recognize the presence of combusting hydrogen, it will stop the flow of gas through the valve. Additionally, a signal can be sent to the electrolyzer to stop the production of hydrogen and protect the closed valve from damage due to pressure.

A hydrogen flame does not conduct electricity sufficient for known flame conduction and rectification systems to operate properly. Known thermocouples respond relatively slowly, which would make a hydrogen flame sensing method that uses a known thermocouple dangerous because a potentially dangerous amount of hydrogen could accumulate before the thermocouple responds. The use of example circuitry 900 shown in FIG. 18 with the thermopile 48 makes it possible to amplify and differentiate the voltage measurements of thermopile 48 so that as the voltage increases, a large output is produced that is easier to recognize and respond to. Once the output of the thermopile 48 is no longer increasing, the steady state gain produces the large output. If the hydrogen flame being monitored by thermopile 48 extinguishes, the output of the thermopile starts to decrease and the differentiated signal drives the output low, even though the thermopile may still be very hot.

The example circuit 900 may function as follows: Resistors R2, R1 and amplifier IC1A produce a steady state gain of 2. Capacitor C1 and R2 with the amplifier IC1A form a differentiator, the maximum gain being limited by C2. Capacitors C3, C2 and C4 act as filters, decreasing the sensitivity to noise ratio, which is advantageous because differentiation is an inherently noisy process. Transistor Q1 pulls the diode D1 to ground and R4 provides a light load so that flame sensing circuitry (not shown) of ignition/pilot system 46 senses a flame. The other half of the amplifier IC1A is not used, but is merely coupled so as to minimize the current drain. A standard thermocouple could also be used if the gain of the circuit were increased. Such a thermocouple could also be adapted to drive the valve 40 in other configurations with different components of the ignition/pilot system 46 removed or modified.

Referring again to FIGS. 1-4, the flame enhancement member 52 is positioned adjacent to the plurality of apertures 56 such that a flame of combusting hydrogen at the surface of the tube burner 50 passes through or at least contacts the flame enhancement member 52. The flame enhancement member 52 may be positioned in contact with the tube burner or may be slightly spaced apart from the tube burner outer surface depending on such considerations as the material of the tube burner and the flame enhancement member, the volume of hydrogen flowing through the openings 56, and the relative flame size and desired flame effect.

The flame enhancement member 52 may include a porous structure that permits passage of combusting hydrogen through the material. Some example porous structures include foam, mesh, and screen structures. Other material structures besides foam structures may also be used so long as the combusting hydrogen can pass through, around or otherwise in contact with the flame enhancement member such that the color of the combusting hydrogen is at least partially changed as a result of contact between the combusting hydrogen and the flame enhancement member. Member 52 may include metals, metal alloys, and other substances that alter an appearance of the flame by, for example, ionizing the combusting hydrogen due to the intense heat generated by the combusting hydrogen to provide coloring of the resulting flame. In one example, the use of a flame enhancement member 52 that includes nickel provides yellow coloring of the flame. Some further example materials that generate specific colors when contacted by a flame are listed in the following Table I. TABLE I Materials Color lithium compounds-masked by barium or sodium Carmine strontium compounds-masked by barium Scarlet or Crimson calcium compounds-masked by barium Yellow-Red sodium compounds Yellow zinc White-Green copper compounds, other than halides; thallium Emerald phosphates Blue-Green antimony and NH₄ compounds Faint Green barium, molybdenum Yellow-Green lead, selenium, bismuth, copper chloride and other Azure copper compounds arsenic and some of its compounds Light Blue CuBr₂, antimony Greenish Blue potassium, rubidium, cesium Purple-Red cupric chloride Blue calcium chloride Orange magnesium ribbon White Sparks iron fillings Yellow Sparks lithium chloride Red sodium chloride Yellow In order to produce a realistic appearing flame or at least a flame that more closely resembles a combusting fibrous material (e.g., wood), the combusting hydrogen is preferably changed to yellow, orange, or red color, or a combination of these colors.

To further enhance the “realistic” appearance of the combusting hydrogen, a blower may be positioned in proximity to the burner to provide a flow of air that alters a position of the combusting hydrogen flame. Such a blower may be modulated thereby providing a modulated air flow that contacts the combusting hydrogen to give the appearance of a modulating flame, which is also common to a flame emanating from a burning fibrous product such as wood.

An example fireplace 800 that includes a blower 804 is shown and described with reference to FIG. 17. Fireplace 800 includes a combustion chamber enclosure 814 in which the blower 804, a stand 806, a log set 810, a burner 850 and a stand 806 are positioned. A fuel source 819 is coupled to the burner 850 via a fuel line 842. A flame 851 generated by the burner 850 may be contacted with a first air stream 802 generated by the blower 804 to alter a position, size, shape, or other physical feature of the flame 851. Heat and other combustion byproducts of the fuel combusted by burner 850 may be moved out of the combustion chamber enclosure 814 by the second air stream 803. The second air stream 803 may be directed out of an open front of the combustion chamber enclosure 814, or may be directed into a plenum or vent system of the fireplace 800.

The blower 504 may be controlled by a controller (not shown) that modulates or otherwise controls the flow of air from the blower 804, thereby further altering the flame 851. Control of the blower 504 may be synchronized with other controlled features of the fireplace 800 such as the flow of fuel from the fuel source 819 to the burner 850, lighting (not shown) and sound (not shown).

A blower may also be used as part of a heat recovery system such as the heat recovery system shown and described in U.S. Pat. No. 6,550,687, which is incorporated herein by reference in its entirety. A heat recovery system associated with the fireplace 10 may also include a moisture recovery and oxygen recovery system (water and oxygen being the by products of hydrogen combustion) (system not shown), which products can be recycled and reused by the fireplace 10 or for other desired purposes.

The fuel source 19 may be any hydrogen generating system that is capable of generating hydrogen fuel and is sized to be disposed within the outer enclosure 12, for example, below the combustion chamber enclosure 14. In other embodiments, the fuel source 19 may be positioned at a remote location from the fireplace 10 and fuel source 19 is coupled to the burner assembly via the first fuel line 42. In still further embodiments, the fuel source 19 and burner assembly 16 may be portable devices that can be moved from one heating appliance to another or function separate from a heating appliance such as, for example, as a fire pit or a fire display device in an outdoor area or within a building structure. FIGS. 8-9 illustrate an example portable burner assembly 216 that is described in further detail below. In still further embodiments, the fuel source 19 represents a fuel distribution system such as is commonly used for distribution of natural gas in urban areas.

Certain features of the burner assembly 16 may be interchangeable with alternative features that have different designs and functions. For example, the tube burner 50 and flame enhancement member 52 may be replaced with the example pan burner 116 shown in FIGS. 5-7. The pan burner 116 includes first and second supports 118, 120, an input member 142 having a mounting bracket 143, a pan burner 150 that includes a gas distribution enclosure 151 having a plurality of apertures 156 formed on a surface thereof, and a flame enhancement member 152 positioned adjacent to the plurality of apertures 156. The “pan” structure of the burner 150 provides a large surface area over which a pattern of apertures 156 may be formed to more closely simulate the burning of a log within the combustion chamber 38 as compared to the tube burner 50 described above. In other embodiments, the pan member 150 may be sized or shaped to simulate the size and shape of a log or stick. Likewise, the flame enhancement member 152 may also be sized and shaped to correspond to the size and shape of at least a portion of the pan portion 150 or a log set (e.g., log set 610 shown in FIG. 15), or may be separately formed and shaped as desired to create a different desired visual effect. Shaping of the flame enhancement member 152 may be performed using any desired methods such as, for example, bending, stamping, casting, molding, spraying, etc. In one example, the flame enhancement member includes a log shape and is configured as a depletable log that is reduced in size as a result of contact with the combusting hydrogen to alter an appearance of the combusting hydrogen flame.

An example of a shaped flame enhancement member is shown in FIG. 12 with reference to the burner assembly 416 that includes a tube burner 450, a shaped flame enhancement member 452 that is coupled to the tube burner with a mounting bracket 453, and a mounting bracket 458 for mounting the tube burner 450 to a source of hydrogen fuel. The shaped flame enhancement member 452 has a semi-circular cross section that substantially matches the outer contour of the tube burner and surrounds a plurality of apertures in the outer surface of the tube burner (e.g., see apertures 56 in FIG. 3).

Another example burner assembly 316 is shown with reference to FIG. 11. Burner assembly 316 includes a molded ceramic pan burner 350 having an upper surface that includes a plurality of contours, and a flame enhancement member 352 that is molded to the upper surface 351. A plurality of apertures 356 are shown for purposes of reference only to illustrate that the flame enhancement member 352 would be positioned vertically above the apertures 356. With the flame enhancement member 352 in proper position, the plurality of apertures 356 would not be visible from the view shown in FIG. 11. Example molded ceramic burner structures are shown and described in U.S. Published Application No. US-2004-0058288-A1, which application is incorporated herein by reference in its entirety. The burner 350 may be made of other inorganic materials that are compression or vacuum molded or cast as the case may be. As noted above, the flame enhancement material 352 may also be molded or otherwise formed directly on the upper surface 351 of the burner 350, or may be adhered, fastened, or otherwise coupled to the burner 350 adjacent to and preferably covering the apertures 356 so as to be in the flow path of combusting hydrogen.

Another example pan burner 550 that includes a molded flame enhancement member 552 is shown with reference to FIGS. 13 and 14. The burner assembly 516 includes an input member 542 having a mounting bracket 543 as well as supports 518 and 520 that maintain the burner 550 in a predetermined position. The molded flame enhancement member 552, as well as all other burner enhancement members described herein, may include contours, shapes, elevations, coloring, texture, and other features (e.g., fiber wool and other simulated ember members) as desired to provide a certain aesthetic effect and appearance.

Referring now to FIGS. 8-10, the stand alone burner assembly 216 includes a pan burner 250, first, second and third supports 218, 219, 220 (a fourth support being not clearly shown), a valve assembly 240, a first fuel line 242, a input member 243, a pilot/ignition system 246 coupled to a pilot system platform 247, a second fuel line 254, and a plurality of apertures 256 formed in the pan burner upper surface 250. The supports 218, 219, 220 provide sufficient support such that the assembly 216 can function as a standalone unit that may be movable for use in any desired location (as noted above). The first fuel line 242 may be coupled to a fixed or portable fuel source such as fuel source 19 described above with reference to FIG. 2. The assembly 216 may also include a flame enhancement member 252 that is coupled to an upper surface 251 (see FIG. 10) for the coloring combusting hydrogen as described above.

The stand alone burner assembly 216 may be used without an exhaust ventilation system as is commonly required for typical decorative fire display devices burning known combustion products such as natural gas and fibrous products. As a result, the assembly 216 could be used in an open room of an enclosed living space without any danger of pollution or the release of harmful substances into the room air. Combusting hydrogen may actually provide an added benefit of increasing the moisture content of the room air and oxygenizing the room air for improved living comfort and health of those residing with the living structure. Alternatively, the oxygen byproduct can be delivered to the combusting hydrogen to aid in combustion. A system or device can be utilized that meters or regulates the amount of oxygen being directed to the combusting hydrogen gas.

Referring now to FIG. 15, an example fireplace 600 is shown including a smoke simulation system. Fireplace 600 includes a combustion chamber enclosure 614 in which a stand 606, a log set 610, a burner 650, and a smoke simulator system 660 are positioned. A fuel source 619 provides fuel to the burner 650 via a fuel line 642, whereby the burner 650 combusts fuel to generate a flame 651. The smoke simulator system 660 includes a water supply 662 in the form of, for example, a pool of water, and first and second transducers 664, 666. The first transducer 664 may be configured to vaporize water from the water supply 662 thereby generating streams of water vapor 668 that can rise separate from or intermixed with the flame 651. The vapor streams 668 may be colored by light generated by a light source 608 that directs light onto the vapor stream and/or the flame 651. The vapor streams 668 may provide the appearance of smoke rising for the flame 651 and log set 610 to improve the aesthetics of the fireplace 600. The second transducer 666 may be used to create movement in the water supply 662 that is viewable to an observer and gives the appearance of an ember bed when the water supply 662 is colored by, for example, the light source 608, flame 651, or coloring in the water itself. In some embodiments, the burner 650 and smoke simulator 660 may be integrated into a single unit.

The light source 608 is positioned vertically below the smoke simulator 660 in FIG. 15, but may be positioned at any location in the combustion chamber enclosure 614 in other embodiments. The fuel source 619 is shown in FIG. 15 at a position below the burner 650, but may be positioned at any location adjacent to or at a location remote from the burner 650. Preferably, the fuel source 619 provides a source of hydrogen fuel to the burner 650 for generation of the flame 651. In some embodiments, the fuel source may be an electrolyzer that generates hydrogen fuel for the burner 650 and water for the water supply 660. The stand 606 may provide support for some features of the features of fireplace 600, or the stand 606 may be removed so that a floor panel 601 of the combustion chamber enclosure 614 provides the necessary support.

Referring now to FIG. 16, an example open pit fire display 700 is shown. The display 700 includes a support platform 714, a stand 706 that may include a fuel source (not shown), a light source 708, a log set 710, an ignition system 746, a burner 750, and a smoke simulator 760. The ignition system 746 may include a thermopile 748 or other device that monitors a pilot flame and/or flames 751 generated by burner 750. The smoke simulator 760 may include a water supply 762 and first and second transducers for generating a vapor stream 768 and simulate embers (not shown). The light source 708 may help alter a color of the vapor stream 768 and flame 758.

The display 700 may be a portable device that can be positioned at any location inside or outside of a living structure. The display 700 may include a self-generating source of fuel such as an electrolyzer that is powered by power cord 707. Alternatively, the electrolyzer can be powered from the wind, solar energy, a generator, battery power, or any combination of these power sources. For example, solar energy can be stored onto batteries for use as needed. Cord 707 may provide power for the ignition system 746, light source 708, and smoke simulator 760.

The display 700 may include a protective viewing panel (not shown) that extends at least partially around the burner 750, for example, around a periphery of the platform 714, to prevent users from accidentally touching the heated burner 750 or other objects heated by the flame 751. Other embodiments may include one or more wall structures that surround the burner to provide, for example, a background such as a brick wall, while the display 700 is open vertically above the burner. Other embodiments may also include a covering oriented vertically above the burner with no surrounding wall structures for the purpose of, or example, protecting the burner from rain when using the display 700 in an outdoor setting while maximizing viewing of the combusting hydrogen from all sides.

The burners and ignition/pilot systems described above may be configured to combust a mixture of hydrogen and alternative fuels. For example, hydrogen fuel may be mixed with liquid propane or natural gas in a fuel mixing chamber at the fuel source or at any other location prior to combustion at the fuel aperture on the surface of the burner. In other embodiments, the pilot light of the system may burn hydrogen while the main burner burns an alternative fuel, or visa versa. In still further embodiments, the burner may be configured with separate apertures at the combustion surface for different fuels. Burning a mixture of hydrogen and an alternative fuel may provide advantages of improved emissions and higher efficiency as compared to burning the alternative fuel alone.

The burners described herein may include any desired materials that would be appropriate for use in this high temperature application. For example, the burner may be a metal member having certain features that are formed using stamping or other forming techniques, while other embodiments may include molded or caste burners. Likewise, the flame enhancement members may be formed using similar methods and may be formed separately or integrally with the burner.

The burners, fireplaces, and systems disclosed herein may be operable using some basic steps of operation illustrated in the exemplary process diagram of FIG. 19. A control signal may be generated 800 using, for example, a remote control device or wire wall-mounted device that activates a fuel source 805 to deliver fuel 810 to a valve that is in fluid communication with a burner. The fuel source may be any source of fuel as described in the above examples such as, for example, an electrolyzer, storage tank, or metal hydride device. The ignition system is then activated 815 and a determination is made as to whether a flame is detected. If a flame is detected 820, the valve is activated to deliver fuel to the main burner for combustion 825. If a flame is not detected 830, the valve is activated to stop the flow of fuel 835. The ignition system at least periodically monitors the presence of a flame to determine if delivery of fuel is still appropriate.

The present invention should not be considered limited to the particular examples or materials described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the instant specification. 

1. A gas fireplace comprising: a combustion chamber enclosure, the combustion chamber enclosure defining a combustion chamber; a burner disposed within the combustion chamber, the burner defining apertures positioned to provide hydrogen gas to a surface of the burner for combustion; and a flame enhancement member positioned relative to the surface of the burner to engage the combusting hydrogen thereby improving visibility of the combusting hydrogen.
 2. The gas fireplace of claim 1, further comprising a hydrogen gas source configured to provide the hydrogen gas to the burner.
 3. The gas fireplace of claim 2, wherein the hydrogen gas source is an electrolyzer.
 4. The gas fireplace of claim 2, wherein the hydrogen gas source is a storage container.
 5. The gas fireplace of claim 2, wherein the hydrogen gas source is a chemical storage device.
 6. The gas fireplace of claim 1, wherein the flame enhancement member comprises porous metal foam, a metal screen, or a metal mesh.
 7. The gas fireplace of claim 1, further comprising an igniter for igniting the hydrogen gas at the surface of the burner.
 8. The gas fireplace of claim 6, wherein the igniter comprises a thermal sensor for monitoring the presence of the combusting hydrogen gas.
 9. The gas fireplace of claim 1, wherein the burner comprises a tube-shaped member defining apertures through which the hydrogen gas passes.
 10. The gas fireplace of claim 1, wherein the burner comprises a pan-shaped member defining apertures through which the hydrogen gas passes.
 11. The gas fireplace of claim 1, wherein the flame enhancement member comprises an ionizing material.
 12. A burner for use in a hydrogen burning appliance, the burner comprising: a gas enclosure defining a gas distribution chamber and a gas aperture; a burner having a combustion surface; a hydrogen gas source coupled to the gas enclosure, wherein the hydrogen gas source supplies hydrogen gas into the gas chamber for distribution to the gas aperture for combustion of the hydrogen gas at the combustion surface; and a flame enhancement member positioned in a path of the combusting hydrogen.
 13. The burner of claim 12, further comprising an igniter configured to ignite the hydrogen gas at the combustion surface.
 14. The burner of claim 12, wherein the flame enhancement member is coupled to the burner.
 15. The burner of claim 12, further comprising a hydrogen gas source to provide the hydrogen gas to the burner.
 16. The burner of claim 12, wherein the hydrogen gas source is an electrolyzer.
 17. The burner of claim 12, wherein the flame enhancement member comprises a porous metal foam.
 18. The burner of claim 12, wherein the ignition system comprises a thermal sensor for monitoring the presence of the combusting hydrogen.
 19. The burner of claim 12, wherein the gas distribution enclosure comprises a tube burner.
 20. A method for generating a visible hydrogen flame, the method comprising the steps of: providing a gas enclosure that defines a gas distribution chamber and a combustion surface having a gas aperture formed therein; supplying hydrogen gas to the gas distribution chamber; passing the hydrogen gas out of the gas aperture; combusting the hydrogen gas at the combustion surface; and passing the combusting hydrogen gas through a flame enhancement member to alter a color of the combusting hydrogen gas.
 21. The method of claim 20, further comprising the step of coupling the flame enhancement member to the combustion surface.
 22. The method of claim 20, further comprising the step of providing an igniter for igniting the hydrogen gas at the surface of the burner.
 23. The method of claim 22, wherein the ignition system comprises a thermal sensor for monitoring the presence of the combusting hydrogen.
 24. The method of claim 20, further comprising the step of providing a hydrogen gas source to supply hydrogen gas to the gas distribution enclosure.
 25. The method of claim 24, wherein the hydrogen gas source is an electrolyzer.
 26. The method of claim 20, further comprising the step of providing oxygen gas to the combusting hydrogen.
 27. The method of claim 20, wherein the flame enhancement member comprises a porous metal foam.
 28. The method of claim 20, wherein the gas distribution enclosure comprises a tube burner.
 29. The method of claim 20, further comprising the step of molding the flame enhancement member to the combustion surface.
 30. The method of claim 20, further comprising the step of positioning the flame enhancement member at a spaced apart location from the combustion surface.
 31. The method of claim 20, wherein passing the combusting hydrogen gas through a flame enhancement member includes ionizing the combustion hydrogen gas.
 32. The method of claim 20, further comprising mixing the hydrogen gas with another fuel prior to passing the hydrogen gas out of the gas aperture.
 33. A fire display assembly, comprising: a burner defining at least one aperture positioned to provide hydrogen gas to a surface of the burner for combustion; a flame enhancement member positioned relative to the surface of the burner to engage the combusting hydrogen thereby improving visibility of the combusting hydrogen; and a support member configured to support the burner and flame enhancement member from vertically beneath the burner and flame enhancement member; wherein the burner is open to ambient air on at least two sides.
 34. The fire display assembly of claim 33, wherein the burner is open to ambient air on all sides and vertically above the burner.
 35. A hydrogen gas burner, comprising: a combustion surface defining a gas aperture configured for delivery of hydrogen gas to the combustion surface for combustion; and a flame enhancement member positioned relative to the gas aperture to contact combusting hydrogen at the combustion surface; wherein the flame enhancement member is configured to alter an appearance of the combusting hydrogen.
 36. The burner of claim 35, wherein the flame enhancement member comprises a solid material.
 37. The burner of claim 36, wherein the flame enhancement member comprises a porous metal foam.
 38. The burner of claim 35, wherein the flame enhancement member is formed directly on the combustion surface.
 39. The burner of claim 35, wherein the flame enhancement member is spaced apart from the combustion surface.
 40. The burner of claim 35, wherein the flame enhancement member is configured to improve visibility of combustion hydrogen.
 41. The burner of claim 40, wherein the flame enhancement member is configured to alter a color of combustion hydrogen. 